The effects of marijuana differ depending on the situation and the individual. In general many experience an elevated mood, which later turns into drowsiness and sedation. Other people report feelings of tranquility and relaxation. Higher-grade marijuana may cause hallucinations.

Negative effects of marijuana use include a feeling of anxiety or fearfulness soon after smoking. Reportedly no only has died from an overdose, but it does impair complex coordination and may contribute to an accident. Up to 48 hours after use, the THC in marijuana may have residual affects on cognitive functioning. The THC in marijuana may be present in the user's body for up to three weeks; in addition, THC may affect the mood and emotional state of the user up to three weeks after initial use.

Those who smoke marijuana face the same health problems that cigarette smokers face. There is speculation that marijuana may affect the immune system negatively. People can become psychologically dependent on marijuana. A tolerance can develop as well as withdrawal after stopping consistent use. Withdrawal effects include anxiety, agitation and illness. For more information on marijuana, health.org is an excellent source.